Additive for leaded gasoline



United States Patent 2,901,335 ADDITI'VE FOR LEADED GASOLINE No Drawing.Application October 5, 1954 Serial No. 460,599

'1 Claims.) cut- 69 This invention relates to gasoline containingtetraethyllead. Moreparticularly the invention relates to leadedgasoline containing additives which increase the stability of..the TEL.and reduce deposits.

1 Gasolines containing tetraethyllead and scavengers associated with TELhave a tendency to deposit insoluble lead decomposition products whilein storage. This instability of the so called leaded gasolines not onlyde creases the octane number of the deteriorated gasoline, but also mayresult in difliculties in the engine from the soluble portions of thedecomposition products. This problem is particularly serious in the caseof leaded gasolines to be used for automotive engines wherein a limithas been imposed of 3.0 cc. of lead fluid per gallon of gasoline. Thusthe octane loss due to lead fluid decomposition cannot be compensatedfor by adding an excess of lead fluid. Although in the case of aviationgasoline as much as 6 cc. of lead fluid has been used, leaddecomposition is very undesirable because of the difiiculty of meetingthe tremendously high octane demand of present performance airplanemotors.

An object" of the invention is a leaded gasoline composition of improvedresistance to deterioration in storage. Another object of the inventionis a leaded gasoline composition of improved stability of the TEL instorage. Other objects will become apparent in the course of thedetailed description of the invention.

The objects of the invention are attained by a composition comprisingessentially a tetraethyllead-eontain- 'ing gasoline as' the majorcomponent and an eifective amount of an additive derived by the reactionof a hereinafter defined amine and a hereinafter defined aminocarboxylicacid.

The amino-carboxylie acids which are suitable for the purposes of theinvention are represented by the configuration: v (1) (CHRMOOOH (CH .0 0OH (II) RN(OHQ)COOH 'wherein x is an integer from 1 to 3 and preferablyx is 1; R is a member selected from the class consisting of (a) Hydrogenand "2 is an integer from 1 to 3.

Iminodiaeetic acid is an example wherein R is hydro gen and x is 1.Ethylenediaminetetraacetic acid is an example wherein R is member (b)and y is 2 and x is l. Tetraethylenepentamineheptaacetic acid is anexample of an acid where R is member (0), x is l, y is 2 and z is 3.

The amino acids of the invention may also be described as aminoaliphatic carboxylic acids wherein at least one amino nitrogen holds 2carboxyalkyl groups.

The amines suitable for the purposes of the invention are: (1) aliphaticamines, either primary, secondary, or tertiary wherein at least onealiphatic group contains at least 8 carbon atoms, and (2) heterocyclicamines which contain at least one aliphatic substituent having at least8 carbon atoms therein and at least one ring nitrogen has a valencewhich is not part of the ring structure, exeluding the pyrrole types.Illustrative examples of these amines are octylamine, decylamine,tetradecylamine, oc tadecylamine, dioctylamine, dioctadecylamine,stearylimidazoline, and oleylimidazoline.

The preferred amines are the fatty acid amines. Those mixtures of amineswhich are obtained from natural vegetable oils, such as palm oil,coconut oil, soya bean oil, tall oil, and cottonseed oil are suitable.Particularly suitable is the mixture of amines derived from tallow. Ofeven greater interest are the high molecular Weight amines which areobtained as a bottoms fraction in the distillative purification of themixture of amines prepared from tallow. These amines are commerciallyavailable under the designation corresponding to the amine product fromthe particular oil or fat, e.g., tallowamine bottoms. The bottomsproduct amines have onedisability in that the quality of the material isvariable and therefore the amine salt of the amino-carboxylic acidproduced therefrom will vary in quality from batch to batch of the aminebottoms material.

The amine salts of amino-carboxylic acids utilizable as hydrocarbon oiladditives are readily prepared by heating the desired amine and thedesired amino-carboxylic acid at a temperature below the decompositiontemperature of the individual components for a suitable period of time.The temperature and the time are dependent upon the particular reactantsused. In general, the temperature at which the reaction is carried outis between about 30 C. and about 200 C.; the time needed for thereaction to be completed Will be between about 15 minutes and about 3hours. It is preferred to utilize a temperature between about C. andabout 180 C.; the corresponding time will be dependent on the type ofreactants charged.

The relative amounts of amine and amino-carboxylic acid utilized isdependent upon the number of carboxylic acid groups in the acid and alsoupon the degree to which the carboxylic acid groups are to be reacted.When it is desired to react all the carboxylic acid groups, it is betterto operate with an excess of amine over the stoichiometric requirement.In general, the molar ratio of amine to acid is between about 0.5 and1.5 of the stoichiometric requirement for reactions with all thecarboxylic groups in the acid. It is preferred to operate with a molarratio of amine and amino-carboxylic acid such that all the carboxylicgroups will be reacted, i.e., at least the stoichiometric requirement.

. The amine salt of amino-carboxylic acid is readily prepared byadmixture of the desired amounts of the reactants and heating themixture to the desiredtemperature and maintaining said mixture at thattemperature for the necessary time. The appearance of the reactantschanges when the reaction begins and completion ofthe reaction isobserved visually by disappearance of the individual reactants. Thereaction product mixture is cooled to room temperature and may beutilized as an additive withoutfurther treatment. However, when an s c2,901,335 f excess of one reactant has been used, it may be desirable topurify the reaction product mixture. This purification is readilycarried out by treating the mixture With a solvent, such as benzene orhexane, filtering to remove the insoluble material and recovering thepurified reaction product, i.e., the amine salt of amino-carboxylicacid, by evaporating away the solvent.

The leaded gasoline which forms the major component of the compositionof the invention may be any mixture of hydrocarbons which meets therequirement with respect to boiling range, freezing point, and sulfurcontent of commercial gasolines for the particular purpose. For example,the commonly called motor gasoline boils over therange from about 100 F.to 400 F. The exactdistribution of components in this boiling rangevaries with the season of the year in order to provide better startingcharacteristics in winter and lower vapor losses in summer. Aviationgasolines generally boil over the range of about 100 F. and 375 F. Insome instances, the socalled aviation safety fuels boil from about 175F. to about 375 F. The composition of the gasoline itself may vary inaccordance with commercial practice. For example, a third-grade fuel maycontain only virgin materials which have been brought to the requiredoctane number by the addition of TEL. In general, the so-called regulargrade gasolines and premium grade gasolines contain cracked components,either thermally cracked, and/ or catalytically cracked, and may containgasoline boiling range polymers from the polymerization of propylene andbutylene and/ or may contain alkylate from the alkylation of isobutane,propylene and butylene. Aviation gasoline, on the other hand, mayconsistalmost entirely of materials derived by various conversion processesfrom petroleum components. For example, aviation gasoline may con tainessentially only alkylate, polymer, and catalytically reformed'naphtha.Benzene and toluene may also he added to some aviation gasolines.

'In addition to the hydrocarbon components, 'gasolines contain variousanti-oxidants, such as N,'N'-di-t-butylparaphenylenediamine and metaldeactivators. Also, they may contain compounds designed to decrease theeffect of TEL decomposition in the combustion chamber, such astricresylphosphate. Furthermore, in addition to the hydrocarboncomponents, the gasoline may contain minor amounts of materials whichassist in good engine performance under specific conditions ofoperation. For example, alcohols and ethers may be present to avoidcarburetor icing. Or. alcohols may be present to prevent formation ofice crystals in storage or in transfer lines. Still further, mostcommercial gasolines contain dyes of one type or another. Also, they maycontain minor amounts of detergent compositions which solubilize waterand prevent formation of a haze.

It is to be understood that the term leaded gasoline used in thisspecification and'in theclaims is intended to include hydrocarbonmixtures which are usable-in. engines of the automotive and airplanetype using spark ignition, which gasolines contain appreciable amountsof tetraetliyllead or the so-called ethyl fluid which consists oftetraethyllead and lead scavengers, as well as theusual additives addedto gasoline, examples of which have been cited above. In general, theamount of tetraethyllead in the formation of TEL fluid which is presentin leaded gasoline is between about 0.5 and 6 cc. per gallon ofgasoline.

The gasoline is thejmajor component of the composition of the invention.The definedamine salts of aminocarboxylic acid are present in an, amountsuificient to lmprove the stability of the tetraethyllead against deteroration in storage. .Generally only a very small amount-ofaminesaltbf.aminocarboxylic acid'is ntilized. "The parti ularamount' used is dependent on the particular use of the composition, butin generalwill be between-about 0.0005 and about 0.5% by weight'of 4 thecomposition. More usually the usage will be between about 0.002% and0.02% by weight.

Examples of the defined amine salts of amino-carboxylic acids are setout below. Illustrations of the compositions containing various amountsof illustrative examples and the beneficial results derived from thepresence of the defined salt in leaded gasoline are set out asdetermined by various tests. It is to be understood that the examples ofthe defined amine salts of aminocarboxylic acids and the illustrativeleaded gasoline comrpesitions containing these salts are illustrativeonly and do not limit the scope of the invention.

SALT I The amine useclin this example is sold by Armour & Co. under thename, Tallowamine Bottoms. This I material is obtained as a bottomsproduct from the dis The amine in this example is sold by Armour .& Co.under the designation Duomeen S. This amine has the structure RNH(CH NHwhere R is an aliphatic group containing 18 carbon atoms. 0.86 mole ofDuomeenS. and 0.46 mole of ethylenediaminetetraacetic acid were stirredat 155 C. for '20 minutes. The product was an orange-yellow in color andcontained 7.91% nitrogenflanfd was soluble in gasoline.

SALT 111 In this example, the amine used is sold by Armour & Co. underthe name, Cocoamine Bottoms. This material is the bottoms product fromthe distillation of the spectrum of amines made from coconut oil. 150 g.of the cocoarnine bottoms and 25 g. of ethylenediarninetetraacetic acidwere stirred at 148 C. for 15 minutes. The productwas diluted with 300ml. of hexane and filtered. The hexane was removed by evaporation. Thebrown waxy solid product was completely soluble in'gasoline and lubeoil. A yield of 173 g. of product containing 2.99% nitrogen wasobtained.

' SALT IV In this example, the amine utilized 'was principallyt-octadecylamine sold under the name of Primene I'M- R. g. of this amineand 20 g. of ethylenediaminetetraacetic acid were stirred at 165 C. for10 minutes. The product was clear orange colored viscous liquidcontaining 5.47% nitrogen and was soluble in gasoline.

SALT V ln this example, the amine was purchasedas-fAlrixamine S. Thismaterial'is. an imidazoline derived "from stearic acid having thefollowing structurez' NOH a( 2)1o IIIOH; R and a molecular weight of360. 43.2 g. (0.12 mole)-'of this imidazoline and 8.76 g. (0.03 mole) ofethylenediaminetetraaceticacid were stirred at 150 C. for 15 minutes.The product weighed 51 g. and was a clear bro wn liquidcontaining 8.28%nitrogen, The product was *solublednlubeOil; V

SALT v1 Iminodiacetic acid (0.1 mole) and 0.2 mole of tallow- ExamplesThe storage stability tests were carried out using 250 ml. of leadedgasoline in a pint bottle provided with a vented stopper. The bottle wasmaintained in a constant temperature room at 90 F. for the time of thetest which may be either 2 or 4 months. At the completion of the storagetime, the contents of the bottle are passed through a filter and thetotal gasoline insoluble deposits are recovered. These are dried andweighed to determine the total deposit as mg./250 ml. of gasoline. Thetotal deposits are then washed with a triple solvent which consists ofequal volumes of acetone, methyl alcohol and chloroform. The materialwhich is insoluble in the triple solvent is dried and weighed to obtaininsoluble deposi as mg./250 ml. of gasoline.

In the first series of tests, a regular grade motor gasoline containing3.0 cc. TEL fluid was used. The storage period was 4 months. The resultsof the test on this 3 cc. containing gasoline are set out in Table I.(0.0018% is 5 lbs./ 1000 bbls. (42 gal.) of gasoline.)

Salts I and II not only reduce the insoluble deposits, but also thetotal deposit. This is a valuable feature in that it definitely improvesthe appearance of the gasoline. While Salts III and IV do not improvethe total amount of deposit formed, they did significantly decrease theamount of insoluble deposits.

Tests Nos. 6 and 7.--In these tests, the gasoline was an aviationgasoline containing 4.5 cc. of TEL fluid per gallon of gasoline. Thetotal time of storage was 2 months. The sample containing no additivedeveloped 3.3 mg. of insoluble deposits (Test No. 6). The samplecontaining 0.0018 weight percent of Salt I developed no measurableamount of insoluble deposit (Test No. 7). 'Ilhese tests show that thesalt obtained by reacting tallowamine bottoms andethylenediaminetetraacetic acid is extremely eitective in inhibiting thedecomposition of tetraethylleacl present in leaded gasoline.

Thus having described the invention, what is claimed is:

1. A composition consisting essentially of a gasoline containing betweenabout 0.5 and 6 cc. per gallon of tetraethyllead and between about0.0005 and 0.5 weight percent of an amine salt of an amino-carboxylicacid obtained by reacting, at a temperature between about 30 C. and 200C., a molar ratio of amine to acid between about 0.5 and 1.5 of thestoichiometric requirement to react all the carboxylic groups in theacid, an amine selected from the class consisting of (1) aliphaticamines wherein an aliphatic group contains at least 8 carbon atoms and(2) imidazoline containing an aliphatic substituent having at least 8carbon atoms is present, with (B) an amino-carboxylic acid having theconfiguration (CH )=O 0 OH (CHQZO 0 OH wherein R is selected from theclass consisting of (a) Hydrogen (011,).0 0 OH and (011,).0 OOH [(0112),N(GH2) .0 0 0H1.(GH,) ,,N

(CHqhOO 011 wherein x is an integer from 1 to 3, y is an integer from 2to 3, and z is an integer from 1 to 3.

2. The composition of claim 1 wherein said salt is obtained by reactingtallowamine bottoms and ethylenediaminetetraacetic acid at a temperaturebetween about C. and C.

3. The composition of claim 1 wherein said salt is obtained by reactingan amine having the structure RNH(CH NH wherein R is an aliphatic groupcontaining about 18 carbon atoms and ethylenediaminetetraacetic acid ata temperature between about 140 C. and 180 C.

4. The composition of claim 1 wherein said salt is obtained by reactingtallowamine bottoms and iminodiacetic acid at a temperature betweenabout 140 C. and 180 C.

5. The composition of claim 1 wherein said amine is stearylimidazoline.

6. The composition of claim 1 wherein said acid istetraethylenepentamineheptaacetic.

7. The composition of claim 1 wherein said salt is present in an amountbetween about 0.002 and about 0.02 weight percent.

References Cited in the file of this patent UNITED STATES PATENTS2,296,200 Cantrell et a1 Sept. 15, 1942 2,564,092 Bersworth Aug. 14,1951 2,573,779 Walters Nov. 6, 1951 2,631,978 Bersworth Mar. 17, 19532,673,144 Huggler Mar. 23, 1954 2,680,094 Bartlett June 1, 19542,700,612 Chenicek Jan. 25, 1955 2,805,203 Knapp et al. Sept. 3, 1957OTHER REFERENCES The Tetrines, Glyco Products Co., Inc., 9-1953, pages2, 3 and 4.

1. A COMPOSITION CONSISTING ESSENTIALLY OF A GASOLINE CONTAINING BETWEENABOUT 0.5 AND 6CC. PER GALLON OF TETRAETHYLLEAD AND BETWEEN ABOUT 0.0005AND 0.5 WEIGHT PERCENT OF AN AMINE SALT OF AN AMINO-CARBOXYLIC ACIDOBTAINED BY REACTING, AT A TEMPERATURE BETWEEN ABOUT 30* C. AND 200*C.,A MOLAR RATIO OF AMINE TO ACID BETWEEN ABOUT 0.5 AND 1.5 OF THESTOICHIOMETRIC REQUIREMENT TO REACT ALL THE CARBOXYLIC GROUPS IN THEACID, AN AMINE SELECTED FROM THE CLASS CONSISTING OF (1) ALIPHATICAMINES WHEREIN AN ALIPHATIC GROUP CONTAINS AT LEAST 8 CARBON ATOMS AND(2) IMIDAZOLINE CONTAINING AN ALIPHATIC SUBSTITUENT HAVING AT LEAST 8CARBON ATOMS IS PRESENT, WITH (B) AN AMINO/-CARBOXYLIC ACID HAVING THECONFIGURATION